In some telecommunications network architectures, TDM-based signaling channels are used to carry signaling information between network nodes. For example, in one network architecture, ISDN primary rate interface (PRI) data (D) channels are used to carry Q.931 signaling between a TDM-based end device, such as a private branch exchange (PBX), and a media gateway controller (MGC) through a signaling gateway (SG). The receiving media gateway may switch the PRI bearer channels to another media gateway or other type of network switch and the signaling gateway may communicate the Q.931 signaling received on the D channels to a media gateway controller. In some instances, the signaling information may be communicated from the signaling gateway to the media gateway controller using Internet protocol (IP). In order to carry Q.931 and other types of signaling over IP, an IETF SIGTRAN adaptation layer, such as GR-303-UA, V5UA, or IUA may be used. As used herein, the term XUA will be used to refer to any of the IETF SIGTRAN or other protocols that provide an adaptation layer to carry TDM-based signaling channels over IP.
In a network architecture such as that described in the preceding paragraph where data received on TDM-based signaling channels is sent to the media gateway controller using Internet protocol, it is desirable to provide redundancy to reduce the impact of failure of the components that perform the Internet protocol conversion or encapsulation. Redundancy can be achieved at the network level by having the communicating endpoints detect the failures and reroute traffic over an alternate link or path. Such an architecture requires both redundant signaling channels and intelligence at the network endpoints to detect failures and route traffic around the failures. Although redundant TDM-based signaling channels, such as redundant D channels, are possible, they are not always implemented by network operators. Also, while protocols such as IUA, provide examples of failovers on the application server process (ASP) or MGC side, IUA does not address failover on the signaling gateway (SG) side. That is, the IUA protocol specification (IETF RFC 4233) does not specify actions to take when an SG fails. Accordingly, in light of these difficulties there exists a need for automatic, peer node transparent re-homing of TDM-based signaling channels in an XUA signaling gateway.